High durable, low-e, heat treatable layer coating system

Abstract

A coated article including a coating supported by a glass substrate is provided. In certain example embodiments, the coating includes from the glass substrate outwardly a first dielectric layer(s), an infrared (IR) reflecting layer (e.g., Ag), NiCrOX layer, at least one dielectric layer including silicon nitride and / or tin oxide, another IR reflecting layer (e.g., Ag), and at least another dielectric layer including silicon nitride and / or tin oxide.

Description

[0001]This application claims the benefit of Provisional Application Ser. No. 60 / 217,101, filed Jul. 10, 2000, the entire content of which is hereby incorporated by reference in this application.[0002]This application is a continuation of application Ser. No. 09 / 795,976, filed Mar. 1, 2001, now U.S. Pat. No. 6,445,503, the entire content of which is hereby incorporated by reference in this application.[0003]This invention relates to mechanically durable layer coating systems particularly useful in laminated, vehicular windshields and insulating glass units. More particularly, this invention relates to such systems which are heat treatable and manifest low values of emissivity.BACKGROUND OF THE INVENTION[0004]Layer coating systems, particularly those formed by the sputter coating process are well known in the architectural and automotive field. Such coatings for solar management purposes seek to achieve among other characteristics, the recuisite reflection of infrared energy and at t...

AI Technical Summary

Benefits of technology

[0031]In still further embodiments, haze, as defined herein, is reduced or eliminated by separating layer (e) above into two seperate layers and imposing between them another layer, preferably of Si3N4, which is believed to reduce stress in at least the two separate layers of SnOx that adjoin this additional layer.

Problems solved by technology

The need for high infrared reflectance and high visible transmittance often conflict with each other.

Making the design of an appropriate, commercial layer system even more difficult is the further need to achieve a desirable (usually substantially neutral) color, and / or low visible reflectivity (i.e., a non-mirror like appearance).

Rather, a major problem that has often faced the I.G. unit and automotive windshield art after an otherwise acceptable sputter-coated layer system has been developed from a solar management and heat treatability perspective, is the need to achieve mechanical durability.

Such handling steps are often of such a nature, in this respect, that the layer coating must be contacted by hand or by some mechanical device, and thus subject to abrasion.

If the coating does not have sufficient “mechanical durability,” numerous rejects caused by scratching, particle abrasion, etc. are likely to occur during the manufacturing process.

Such a problem is particularly acute in the laminated (vehicular) windshield and the insulating glass unit (I.G. unit) arts.

Thereafter, in the making of a typical laminated windshield, numerous procedures are engaged in which require such potentially mechanically damaging steps as suction cup lifting, edge grinding, racking for shipment, flipping, separation using particles of diatomaceous earth and the like.

The need for a highly durable layer coating system in such a product is self evident and its achievement is a known problem, as aforesaid, in the art

However, the systems disclosed were not heat treatable and thus could not realistically be used where bent windshields were involved, or other heat treatments such as tempering or heat strengthening or glass welding were later contemplated.

The systems contemplated, however, are non-silver containing and thus could not avail themselves of the advantages of silver in achieving certain solar management properties, particularly infrared energy reflection, for which silver is commonly used in the sputter coating art.

This system is heat treatable but loses mechanical durability upon heat treatment and generally demonstrates poor chemical durability.

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